Brimmed-diffuser augmented wind turbines (B-DAWTs) can significantly increase the performance of the rotor. Multi-rotor systems (MRSs) have a lot of merits such as significant saving mass and overall cost of the wind turbine system. In the present research, B-DAWTs are studied in a MRS. In wind tunnel experiments, the power output and aerodynamics of two and three B-DAWTs placed in close vicinity have been investigated. Results show a significant increase of up to 12% in total power output of the MRS with B-DAWTs compared to the sum of the stand-alone same turbines. The accelerated gap flows between B-DAWTs in a MRS cause lowered pressure regions due to vortex interaction behind the brimmed diffusers and draw more wind into turbines.